Several publications and patent documents are referenced throughout this application in order to more fully describe the state of the art to which this invention pertains. The disclosure of each of these publications and patent documents is incorporated by reference herein.
Pine barrens (pinelands) comprise a unique type of eco-system that is oligotrophic, and both drought- and fire-prone. Pine barrens occur throughout northeastern USA from New Jersey to Maine (Forman et al. 1998). Pines and oaks are the most common trees in pine barrens, while the understory is composed of grasses (Poaceae), sedges (Cyperaceae), blueberries and other members of heath family (Ericaceae). The largest and most uniform area of pine barrens in the United States is the 1.4 million acre pine barrens of New Jersey, where the soil is highly acidic, sandy and nutrient poor.
Dark septate endophytes (DSE) refer to a group of heterogeneous plant root-colonizing ascomycetes that produce melanized, septate hyphae. They have been isolated from over 110 plant families that grow in various environments (Knapp et al. 2012). The best studied DSE are the Phialocephala fortinii-Acephala applanata complex (PAC), a group of asexual fungi in Helotiales of Leotiomycetes (Wang et al. 2006). Fungi in PAC are characterized by darkly pigmented hyphae, and typically produce branched conidiophores, hyaline phialides with collarettes, and intracellular microsclerotia (Grünig et al. 2008a, 2008b; Yu et al. 2001). PAC are the common root associates of many tree species, specifically conifers in forests of the northern hemisphere (Grünig et al. 2008a, 2008b; Menkis 2004). Despite the global pervasiveness of DSE, their ecological roles, phylogenetic relationships and taxonomy remain poorly understood (Knapp et al. 2012; Mandyam and Jumpponen 2005). DSE fungal-plant interaction studies have yielded variable results, likely due to the use of differing experimental design strategies (Grünig et al. 2008b).
It is estimated that 30% of the world's total land area consists of acid soils, and 50% of the world's potential arable lands are acidic (Tuininga et al. 2004). In view of these adverse environmental conditions, improved methods to enhance growth of both edible and non-edible plants are needed.